Dual venturi anesthetic gas circulating device



Aug. 26, 1969 w. B. NEFF 3,463,151

DUAL VENTURI ANESTl-IETIC GAS CIRCULATING DEVICE Filed Sept. 7, 1965 I NV EN TOR. I Are. MLLMMBMFF'.

- BY I ,q-rfpauly United States Patent 3,463,151 DUAL VENTURI ANESTHETICGAS CIRCULATIN G DEVICE William B. Neif, 11 Granite Court, San Carlos,Calif. 94070 Filed Sept. 7, 1965, Ser. No. 485,417 Int. Cl. A61m 17/00;F04b 39/10 US. Cl. 128188 4 Claims ABSTRACT OF THE DISCLOSURE Thisinvention relates generally to apparatus for the administration ofanesthetic gases and more particularly to a device for maintaining acontinuous circulation of anesthetic atmospheres within the carbondioxide absorbing circuit of an anesthetic gas administrating machine.

An object of the invention is to provide a circulation inducing means ofan improved character for the breathing system of anesthetic gasadministrating machines and similar apparatus.

A further object of the invention is to provide a gas circulating meansfor anesthetic gas administrating apparatus that requires no movingparts and which will enable a patient to breathe with a minimum ofeifort.

Another object of the invention is to provide a gas circulating meansfor anesthetic gas administrating and similar apparatus in which the gasis circulated by a dual Venturi means embodying improved features ofconstruction.

A further object of the invention is to provide a Venturi tubecirculating means for a continuous flow closed circuit anesthetic gasadministrating system in which the circulation of the anesthetic gas ismaintained directly from the feed tube of a gas administrating machinerather than by an external source of power and in which any excess inthe flow of gases required to power the Venturi is automaticallyrelieved into the breathing system.

Other objects and advantages of the invention will be in part evident tothose skilled in the art and in part pointed out hereinafter in thefollowing description taken in connection with the accompanying drawingwherein there is shown by way of illustration and not of limitation apreferred embodiment of the invention.

In the drawing wherein like numerals refer to like parts throughout theseveral views:

FIGURE 1 is a sectional view taken along a vertical plane at the centerof my gas circulating means,

FIGURE 2 is a transverse sectional view taken along line 2-2 of FIGURE1, looking in direction of arrows,

FIGURE 3 is a similar sectional view taken along line 3-3 of FIGURE 1,looking in direction of arrows,

FIGURE 4 is a similar sectional view taken along line 4--4 of FIGURE 1,looking in direction of arrows, and

FIGURE 5 is a diagrammatic illustration showing my invention as employedin a continuous flow anesthetic gas circulating system.

Reference is now made to FIGURE 1 of the drawing wherein my device isshown as consisting of a main body member, designated by the numeral 10,which may be of metal, a plastic or of ceramic material having twoVenturi throats or passageways 11 that operate in conjunction withassociated jet producing nozzles 12 to maintain a circulation of gasthrough the breathing system. At the discharge end of the body member 10there is a reducing coupling 13 which is threaded thereupon and sealedby a gasket 14. At its other end, the body member 10 has a gas atomizingchamber forming shell 15 that is secured thereupon by suitable meanssuch as screws 16 and is sealed by means of a gasket 17. The shell 15has an outer auxiliary chamber 18 having a threaded coupling 19 with anipple 20 by which a connection is made to a source of anesthetizing gasunder pressure. In addition to the Venturi throats, the main body member10 also has a chamber 21 within which there is mounted a pressure reliefor by-pass valve 22 that is associated with an extending conduit 23 thatis disposed within a reduced cylindrical bore 24 communicating with thechamber 21 of the body member 10. This conduit 23 forms a directconnection with the auxiliary chamber 18 into which the anesthetizinggases are initially introduced when the device is in operation. Theby-pass or pressure relief valve 22, as here shown, has a stem 25 thatextends through a threaded bushing 26 having a plurality of spacedopenings 27 through which gases may flow when the valve 33 is in itsopen position. In this arrangement, the bushing 26 is threaded into thechamber 21 and provides a means for adjusting the effectiveness of acoiled compression spring 28 that serves to maintain the by-pass valve22 in its normally closed position. In addition to the reducing coupling13 at the discharged end of the body member 10, the shell 15 is shown ashaving a downwardly extending inlet conduit 29 through which thereturned anesthetizing gases, after passing through a C0 absorber orcanister may reenter the breath circulating system as will be pointedout in more detail hereinafter.

Before proceeding further with reference to the remaining figures of thedrawing, it should be pointed out that the Venturi throat 11 of themember 10, to simplify the drawing, is shown as located along thecentral plane of the body member 10. However, in actual construction,the dual Venturi throats 11 of the body member 10 are, as shown inFIGURES 2 and 3 of the drawing, disposed in equally spaced relation atopposite sides of the central vertical plane of the device, and the jetproducing nozzles 12 are likewise arranged at the sides of the centralvertical plane and in line with the Venturi throats 11 as shown inFIGURE 4 of the drawing.

In FIGURE 5 of the drawing, there is schematically shown a closedanesthetic breathing system in which my Venturi circulator powered froma source of anesthetic gas is connected through a flexible inhalebreathing tube 30 to a fitting 31 at one side of a face mask 32.Opposite the fitting 31, the face mask 32 has a second fitting 33 whichcarries a flexible exhale breathing tube 34. The tube 34 leads to abreathing bag 35 that is interposed in a connection with a C0 absorbingcanister 36. As here shown, the canister 36 is connected at its upperend to the inlet conduit 29 of the circulator which communicates withthe interior of the chamber forming shell 15 where the two jet producingnozzles 12 of the Venturi are located. With this arrangement, when asource of anesthetic gas is introduced at the nipple 20, the gas willenter the auxiliary chamber 18 and then to nozzle 12. This willestablish a continuous circulation of anesthetic atmospheres within theCO absorbing circuit of any standard anesthetic gas machine. Theanesthetic gases and vapors will be projected through the jet producingnozzles 12 and this will power the two parallel Venturis so that theentire anesthetic atmospheres will pass through the throats of theVenturi in a unidirectional manner and thus eliminate any need for flowdirection controlling valves. The throats of the Venturi will preferablyhave a total crosssectional area at least equal to if not greater thanthe cross-sectional area of the most restricted portion of the breathcirculating system. In practice, it has been found that 3 litre/minuteflow of the anesthetic gas is sufiicient to power the Venturis andmaintain a circulation of 30 litre/ minute flow of gas in the breathingsystem. Should it be desired to quickly fill the breathing bag withemergency oxygen or anesthetic gas, the gases greater than the flowrequired to power the dual Venturis will then enter the generalcirculation of the anesthetic atmosphere through the by-pass valve 22.This, therefore, makes it possible to more quickly fill the breathingbag than would be the case if this excess gas had to be projectedthrough the Venturi throats of the circulator. The system here disclosedand schematically shown, will perform optimally without the use of flowdirection controlling valves. However, any such valves in a standard COabsorbing circuit may be left in the system as an indicator of thesoundness of the anesthesia machine when powered by my dual Venturicirculating device. To eliminate the undermask dead-space, I have shownthe face mask 32 as having an inhalation port at one side and anoppositely disposed exhalation port which will put the undermask spacein the circuit of the anesthetic atmosphere breathed in by the patient.A conventional face mask with a By-Y coupling may also be used with mycirculator. By assisting the patient in this manner, the anesthetic gas,after passing through the CO absorber circuit, will keep the undermaskatmosphere sweet and permit the patient to breathe with less effort.

While I have, for the sake of cleamess and in order to disclose myinvention so that the same can be readily understood, described andillustrated a specific form and arrangement, I desire to have itunderstood that this invention is not limited to the specific formdisclosed, but may be embodied in other ways that will suggestthemselves to persons skilled in the art.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In an anesthetic gas administering system, the combination of a gascirculating means having an elongated body member, a coupling at one endof said body member connected with the inhalation conduit of a facemask, a face mask having an inhalation and an exhalation conduitextending therefrom, a C0 gas absorbing canister and a breathing sackconnected in the exhalation conduit of said face mask, an atomizingchamber forming shell at the oher end of said body member having an openport through which the exhaled gases after pasing through the CO gasabsorbing canister will flow from the face mask, an auxiliary chambercarried by said shell into which anesthetizing gas under pressure isfirst introduced from a suitable source of supply, said elongated bodymember having spaced Venturi passageways extending from said atomizingchamber and exhausting into the coupling at the end of said body member,atomizing jet producing nozzles disposed within said chamber formingshell in cooperating relation with the Venturi passageways of said bodymember and extending from said auxiliary chamber for projecting jets ofgas under pressure from said auxiliary chamber through said Venturipassageways, whereby a substantially constant flow of refreshedanesthetizing atmosphere wil be maintained in the breathing circuit ofthe face mask when the circulating means is in operation, said bodymember also having a normally closed by-pass conduit leading from saidauxiliary chamher and extending in parallel relation with the Venturipassageways of said body member, and a pressure responsive valve meansin said by-pass conduit operating to admit anesthetizing gas from theauxiliary chamber and into a breathing circuit of the system whenanesthetizing gas is required in excess of that provided for by theVenturi passageways in said body member.

2. The invention as set forth in claim 1, characterized by the fact thatthe by-pass in said body member is of two different axially relateddiameters, said pressure responsive valve means in the larger diameterof said bypass biased into closing relation with the smaller diameter ofthe by-pass, a spring means biasing said valve means, and a threaded andapertured plug at the open end of said conduit for varying the responseof said valve means to pressure exerted thereupon.

3. The invention as set forth in claim 2, characterized by the fact thatthe normally cosed by-pass conduit of said body member is of twodiffering coaxial dimensions forming a shoulder intermediate the endsthereof, a valve means engaging the shoulder in said passageway forclosing said by-pass conduit, and a nipple extending from said auxiliarychamber in sealed contact with the smaller diameter end of said by-passthrough which anesthetizing gas may flow directly from said auxiliarychamber independently of said Venturi passageways when said valve memberis in its open position.

4. A gas circulating device for an anesthetizing gas administeringsystem, comprising a main body member having a Venturi passagewaytherethrough with a by-pass conduit extending parallel with said Venturipassageway, means carried by said main body member forming a gasatomizing chamber at the smaller end of the Venturi pasageway of saidbody member, an atomizing jet producing nozzle disposed within saidchamber in alignment with said Venturi passageway adapted to beconnected with a source of gas under pressure, said chamber also havingan inlet opening through which exhaled atmosphere may enter saidchamber, coupling means at the other end of said body member adapted tobe connected with the inhalation side of a face mask, characterized bythe fact that a nipple connects said by-pass directly with thepressurized source of anesthetizing gas, and a pressure responsive valvemeans located in the by-pass of said body member adapted and arranged toopen when the required volume of anesthetizing gas is greater than thatcirculating through said Venturi passageways when the circulating meansis in operation.

References Cited UNITED STATES PATENTS 1,737,575 12/1929 Driiger 128-191XR 1,804,569 5/1931 Taddiken 230103 2,057,218 10/ 1936 Timpson.2,525,256 10/1950 Byram 103-271 XR 2,891,542 6/1959 Pentecost 128-188WILLIAM E. KAMM, Primary Examiner US. Cl. X.R. 230-103

